Remove broken "Edit on GitHub/Bitbucket" link from search pages

On a page of search results, the "Edit on GitHub/Bitbucket" link tries
to send the reader to a file "search.rst" or "search.txt" in the
repository. Since the search results only exist as a template, this is
a 404'd link.

This change to the template means that the "Edit on GitHub/Bitbucket"
link is not shown on search pages, getting rid of this broken link.

sphinx_rtd_theme/breadcrumbs.html

@@ -6,6 +6,7 @@
       {% endfor %}
     <li>{{ title }}</li>
       <li class="wy-breadcrumbs-aside">
+        {% if pagename != "search" %}
           {% if display_github %}
             <a href="https://{{ github_host|default("github.com") }}/{{ github_user }}/{{ github_repo }}/blob/{{ github_version }}{{ conf_py_path }}{{ pagename }}{{ source_suffix }}" class="fa fa-github"> Edit on GitHub</a>
           {% elif display_bitbucket %}
@@ -15,6 +16,7 @@
           {% elif show_source and has_source and sourcename %}
             <a href="{{ pathto('_sources/' + sourcename, true)|e }}" rel="nofollow"> View page source</a>
           {% endif %}
+        {% endif %}
       </li>
   </ul>
   <hr/>